The reason why a CPLD family
was chosen for this job is the fact that your
allowed to watch the Boolean Equations which
comes as a result of the Synthesize program.

**Note segment a:
** It seems that
this equation "pretty much" the same we would
get by using a Carnaugh map.

**Note segment b: **
This equation doesn't look
like the result from above - the synthesize tool
simply taking advance of the fact that
product-terms and equations from all segments
can be "re-cycled" and hence can a lot of logic
be saved.

*
Even a skilled
engineer will have a hard time doing this with
Carnaugh maps *

But the optimization doesn't
stop here, please take a look at the VHDL
solutions - even more optimized solutions
possible.